Add Python 3.12.x to the test matrix.

Author: rlubke

.github/workflows/validate.yml

@@ -17,7 +17,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python-version: ["3.8.x", "3.9.x", "3.10.x", "3.11.x"]
+        python-version: ["3.8.x", "3.9.x", "3.10.x", "3.11.x", "3.12.x"]
         poetry-version: ["1.5.0"]
         os: [ubuntu-latest]
         coherenceVersion: